1. Field of the Invention
The present invention relates to digital multimedia broadcasting (DMB), and more particularly, to a broadcast signal and a broadcast receiver and method for decoding the same.
2. Discussion of the Related Art
Digital broadcasting has affected the existing analog radio broadcasting so as to expedite the introduction of digital radio broadcasting. Also, the digital broadcasting makes it possible to provide a digital multimedia broadcasting (DMB) service including data transmission and multimedia services as well as the existing audio radio service.
The DMB adopted by Korea is based on Eureka-147 digital audio broadcasting (DAB) adopted as European terrestrial radio standard. In order to enhance more efficiently multimedia broadcasting performance, Reed-Solomon code and Convolution Interleaver that are robust against burst error on a transmission channel are added to the DAB.
Accordingly, the DMB is robust against noise and distortion on the transmission channel, has high transmission efficiency, and can provide various multimedia services.
Specifically, the transmission channel of the DMB serves as a wireless mobile reception channel and its amplitude is time-varying. Also, Doppler spreading of a received signal spectrum occurs due to the influence of the mobile reception. Considering the transmission/reception under such a channel environment, the DMB transmission method is based on Coded Orthogonal Frequency Division Multiplexing (OFDM).
Since the OFDM scheme uses a plurality of multi-carriers, it is robust against ghost that may occur due to the multi-path. Also, the OFDM scheme has an advantage in that a channel estimation based on a pilot signal is convenient.
The Eureka-147 has been introduced for the DAB but the Eureka-147 has been used as fundamental technology of a terrestrial DMB technology for providing a video service of a small sized moving picture by using a narrow frequency bandwidth of 2 Mhz. Eureka-147 system provides an expandable structure for transmitting multimedia data. That is, the Eureka-147 system provides a packet mode or a stream mode for transmitting the multimedia data. Accordingly, multimedia data can be transmitted with minimum modification of a conventional terrestrial DAB system in the Eureka-147 system.
At this time, the terrestrial DMB service is required to provide multimedia services even under a moving environment regardless of place. In this respect, for service quality, it is important that a shaded area of the downtown, such as building and subway, be provided with a re-transmitter.
In other words, the re-transmitter is provided in a shaded area where it is difficult to receive DMB service due to subway, building areas, a high-rise building, and so on. Thus, the re-transmitter serves as a relay that receives the DMB service transmitted from a broadcasting station and re-transmits the DMB service to a DMB receiver placed in the shaded area.
However, since the terrestrial DMB service is fundamentally provided free of charge, a service provider should bear much expense in ensuring a service area for providing many re-transmitters.